Scale inhibitor suitable for high-chlorine high-calcium-magnesium water as well as preparation method and application of scale inhibitor

Abstract

The invention relates to the technical field of water treatment agents, and provides a scale inhibitor suitable for high-chlorine high-calcium-magnesium water and a preparation method and application thereof.The scale inhibitor comprises a deionized water-absolute ethyl alcohol solution and four active components, and the total mass of the four active components is 100%. The corrosion inhibitor comprises the following components in percentage by weight: 70-74% of a sulfophosphine synergistic modified polyaspartic acid derivative, 10-13% of a natural polyphenol complexing agent, 12-14% of zwitterionic polycarboxylate and 1-2% of a nitrogen heterocyclic corrosion inhibitor. The total mass fraction of the four active components is 25%-35%, the mass fraction of the absolute ethyl alcohol is 5%-10%, and the balance is deionized water based on the total mass of the descaling agent being 100%. According to the invention, main chain sulfophosphine modified polyaspartic acid is grafted with a sulfonic acid group and a phosphonate group, molecular chain dispersibility is maintained, Ca < 2 + > and Mg < 2 + > are chelated, bridging of metal ions is prevented, absolute ethyl alcohol is added to improve compatibility of four active components, dispersion is stable, and scale inhibition efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of water treatment agent technology, specifically to a scale inhibitor suitable for high-chlorine, high-calcium, and high-magnesium water, its preparation method, and its application. Background Technology

[0002] During oil and gas field development, surface reinjection water / produced water treatment systems face severe scaling problems. These water bodies typically have extremely high mineralization (total dissolved solids (TDS) 200,000~300,000 mg / L) and high chloride ion content (Cl... - High levels of calcium and magnesium ions (Ca) often exceed 80,000 mg / L, and in some operating conditions reach over 200,000 mg / L. 2+ +Mg 2+ The scale concentration is typically >5000 mg / L, with some reaching 25000 mg / L. The main scale type is CaCO3, accompanied by small amounts of CaSO4 and SrSO4. Under certain high-magnesium conditions, MgCO3 or Mg(OH)2 scale may also form. Scale formation can lead to blockage of water injection pumps, reduced heat exchanger efficiency, and filter failure, severely impacting oil and gas field production efficiency and significantly increasing equipment maintenance costs.

[0003] Currently, the scale inhibitors commonly used in oil fields mainly include the following categories:

[0004] 1. Organophosphonic acids: such as HEDP (hydroxyethylidene diphosphonic acid), ATMP (aminotrimethylenephosphonic acid), DTPMP (diethylenetriaminepentamethylenephosphonic acid), etc. These agents have good scale inhibition effects on CaCO3, but they have poor biodegradability, easily cause eutrophication of water bodies, and under high calcium conditions, they easily form insoluble calcium phosphonate precipitates, which can actually exacerbate scaling.

[0005] 2. Polycarboxylic acid derivatives: such as polyacrylic acid (PAA), polymethacrylic acid (PMA), etc. Although these agents have some dispersibility, they are suitable for high chloride ion (Cl...) - >100000 mg / L), high calcium and magnesium ions (Ca 2+ In environments with concentrations >10000 mg / L, molecular chains aggregate due to charge shielding effects, resulting in a significant decrease in scale inhibition efficiency, especially with almost no inhibition of MgCO3 scale.

[0006] 3. Existing compound products: Most of them use phosphonic acid and polymers for simple mixing, which is difficult to adapt to extreme high chloride and high calcium and magnesium conditions, lacks broad-spectrum inhibition ability for various scale types, and cannot solve the synergistic problems of equipment pitting corrosion and stress corrosion cracking caused by high chloride ions, making it difficult to meet the long-term stable operation requirements of oil and gas field water treatment systems. Summary of the Invention

[0007] The purpose of this invention is to solve the technical problems of existing scale inhibitors being prone to molecular chain aggregation in high-chlorine, high-calcium, and high-magnesium water, resulting in decreased scale inhibition efficiency and inability to solve the synergistic corrosion of equipment caused by high chloride ions. This invention provides a scale inhibitor suitable for high-chlorine, high-calcium, and high-magnesium water, which can solve the above problems.

[0008] To achieve the above objectives, this invention provides a scale inhibitor suitable for high-chlorine, high-calcium, and high-magnesium water, comprising a deionized water-anhydrous ethanol solution and four active components. The four active components, based on 100% of their total mass, are as follows by mass percentage: 70-74% sulfonylphosphonate-modified polyaspartic acid derivative, 10-13% natural polyphenol complexing agent, 12-14% zwitterionic polycarboxylate, and 1-2% nitrogen-containing heterocyclic corrosion inhibitor. Based on 100% of the total mass of the scale inhibitor, the total mass fraction of the four active components is 25%-35%, the mass fraction of anhydrous ethanol is 5%-10%, and the remainder is deionized water. The sulfonylphosphonate-modified polyaspartic acid derivative has polyaspartic acid as the main chain, which is a functionalized polymer by grafting sulfonic acid groups and phosphonate groups. This solution avoids molecular chain aggregation through three design aspects: the main chain of sulfonylphosphonate-modified polyaspartic acid is grafted with sulfonic acid groups and phosphonate groups; the sulfonic acid groups can resist chloride ions (Cl). - Charge shielding maintains molecular chain dispersion; phosphonate groups can chelate Ca. 2+ and Mg 2+ It prevents metal ion bridging, stops molecular chain aggregation at the source, and adds anhydrous ethanol to improve the compatibility of the four active components, further preventing molecular chain curling, assisting in the stable dispersion of molecular chains, and improving scale inhibition efficiency.

[0009] Preferably, the repeating unit structure of the polyaspartic acid backbone has the general formula -[NH-CH(CO2H)-CH2-CO]-, and the number average molecular weight is 3000 Da~6000 Da; in every 100 repeating units on the backbone, 25~35 nitrogen atoms are covered by -CH2CH(OH)CH2SO3 - The group is substituted and 8 to 12 -P(O)(OR)OH groups are grafted, wherein R is a C1-C4 alkyl group.

[0010] Preferably, the natural polyphenol complexing agent is a plant polyphenol containing a catechol structure, specifically a purified epigallocatechin gallate derivative. The natural polyphenol complexing agent reacts with Ca... 2+ It forms a stable, soluble complex, inhibits crystal nucleus formation, and reacts with Fe on the metal surface. 2+ They combine to form a dense protective film, achieving auxiliary scale inhibition and synergistic corrosion inhibition functions.

[0011] Preferably, the zwitterionic polycarboxylate includes betaine-type side chains with a side chain density of 1.0~1.2 mmol / g. As a dispersant and stabilizer, the zwitterionic polycarboxylate can prevent the aggregation of CaSO4 and MgCO3 microcrystals, avoiding the formation of dense scale layers. It also synergistically enhances the inhibition effect of sulfate and magnesium scale by working with sulfonylphosphonate-modified polyaspartic acid derivatives.

[0012] Preferably, the nitrogen-containing heterocyclic corrosion inhibitor is an alkylated benzotriazole derivative, selected from methylbenzotriazole, ethylbenzotriazole, or propylbenzotriazole. Alkyl modification enhances the adsorption capacity in high-salt environments, forming a dense adsorption film on the carbon steel surface and preventing Cl- from adsorbing. - It penetrates the passivation film to prevent high chloride ion corrosion of the equipment.

[0013] A method for preparing a scale inhibitor for high-chlorine, high-calcium, and high-magnesium water includes the following steps:

[0014] S1. Add sulfophosphonate-modified polyaspartic acid derivative, natural polyphenol complexing agent, zwitterionic polycarboxylate, and nitrogen-containing heterocyclic corrosion inhibitor into a container in proportion to form a mixture.

[0015] S2. Add 5-10% anhydrous ethanol to the mixture to bring it up to the total mass of the final product, and obtain the scale inhibitor product.

[0016] S3. Add deionized water until the total mass reaches 100%, then stir and mix.

[0017] Preferably, step S1 further includes a step for preparing a sulfonylphosphonate-synergistic modified polyaspartic acid derivative, specifically:

[0018] S11. Dissolve polyaspartic acid in deionized water to prepare a 20-30 wt% solution, add sodium 3-chloro-2-hydroxypropanesulfonate, and stir to react;

[0019] S12. Prepare a second solution of dimethyl phosphonite and 2-chloroethanol according to the molar ratio of polyaspartic acid repeating unit: dimethyl phosphonite: 2-chloroethanol = 1:0.2~0.4:0.1~0.2, and add the second solution to the first solution;

[0020] S13. After cooling, an aqueous solution of sulfonylphosphonate-modified polyaspartic acid derivative was obtained.

[0021] Preferably, in step S2, the stirring is carried out continuously at a stirring rate of 300~500r / min for 1~1.5h. After stirring is completed, impurities are filtered out using a 0.22μm organic filter membrane.

[0022] Preferably, an acidification drag-reducing agent suitable for carbonate reservoirs is used in acidified carbonate reservoirs.

[0023] The beneficial effects of the invention are: the main chain sulfonylphosphonate modified polyaspartic acid grafted with sulfonic acid groups and phosphonate groups, the sulfonic acid groups can resist Cl - Charge shielding maintains molecular chain dispersion; phosphonate groups can chelate Ca. 2+ and Mg 2+ It prevents metal ion bridging, stops molecular chain aggregation at the source, and adds anhydrous ethanol to improve the compatibility of the four active components, further preventing molecular chain curling, assisting in the stable dispersion of molecular chains, and improving scale inhibition efficiency. Attached Figure Description

[0024] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0026] In this disclosure, unless otherwise stated, directional terms such as "inner" and "outer" are defined based on the contours of the corresponding components. Terms such as "first" and "second" used in this disclosure are for distinguishing one element from another and do not imply sequence or importance.

[0027] This invention provides a scale inhibitor suitable for high-chlorine, high-calcium, and high-magnesium water, comprising a deionized water-anhydrous ethanol solution and four active components. The four active components, based on 100% of their total mass, are as follows by mass percentage: 70-74% sulfonylphosphonate-modified polyaspartic acid derivative, 10-13% natural polyphenol complexing agent, 12-14% zwitterionic polycarboxylate, and 1-2% nitrogen-containing heterocyclic corrosion inhibitor. Based on 100% of the total mass of the scale inhibitor, the total mass fraction of the four active components is 25%-35%, the mass fraction of anhydrous ethanol is 5%-10%, and the remainder is deionized water. The sulfonylphosphonate-modified polyaspartic acid derivative is a functionalized polymer with polyaspartic acid as the main chain, grafted with sulfonic acid groups and phosphonate groups.

[0028] To prevent molecular chain aggregation, a three-pronged design approach is employed: sulfonylphosphonate-modified polyaspartic acid derivatives are used as the main scale inhibitor; the main chain of sulfonylphosphonate-modified polyaspartic acid is grafted with sulfonic acid groups and phosphonate groups; and the sulfonic acid groups can resist Cl... - Charge shielding maintains molecular chain dispersion; phosphonate groups can chelate Ca. 2+ and Mg2+ It prevents metal ion bridging, stops molecular chain aggregation at the source, and adds anhydrous ethanol to improve the compatibility of the four active components, further preventing molecular chain curling, assisting in the stable dispersion of molecular chains, and improving scale inhibition efficiency.

[0029] The anhydrous ethanol accounts for 5-10% of the total mass of the descaling agent, and anhydrous ethanol acts as a co-solvent to improve the compatibility of the components; the total mass of the descaling agent is replenished to 100% by deionized water, and deionized water acts as a solvent carrier to adjust the concentration of the system; wherein, the mass percentage of all non-deionized water and non-anhydrous ethanol components is the total solids content, and the total solids content is the mass fraction of the four active components in the total mass of the descaling agent, and the total solids content is 25%-35%.

[0030] The repeating unit structure of polyaspartic acid backbone has the general formula -[NH-CH(CO2H)-CH2-CO]-, and the number average molecular weight is 3000Da~6000Da;

[0031] The general structural formula is -[NH-CH(CO2H)-CH2-CO]. n -, n represents the degree of polymerization of the main chain, where 25-35 nitrogen atoms in every 100 repeating units on the main chain are bonded to -CH2CH(OH)CH2SO3. - The group is substituted and 8 to 12 -P(O)(OR)OH groups are grafted, wherein R is a C1-C4 alkyl group, and R is preferably methyl or ethyl.

[0032] The natural polyphenol complexing agent serves as an auxiliary scale inhibitor. This natural polyphenol complexing agent is a plant polyphenol containing a catechol structure, specifically a purified epigallocatechin gallate derivative (EGCG), with the chemical formula C. 22 H 18 O 11 The molecular weight is 458.37, and the CAS number is 989-51-5; the purity of the natural polyphenol complexing agent is ≥95%, the particle size is ≤10μm, and it does not hydrolyze under high chloride ion conditions. The natural polyphenol complexing agent reacts with Ca... 2+ It forms a stable, soluble complex, inhibits crystal nucleus formation, and reacts with Fe on the metal surface. 2+ They combine to form a dense protective film, achieving auxiliary scale inhibition and synergistic corrosion inhibition functions.

[0033] The zwitterionic polycarboxylate includes a betaine-type side chain with a density of 1.0~1.2 mmol / g, and the betaine-type side chain is: -N + (CH3)2-CH2-COO - Amphoteric polycarboxylate, as a dispersant and stabilizer, can prevent the aggregation of CaSO4 and MgCO3 microcrystals, thus avoiding the formation of dense scale. It also synergistically enhances the inhibition effect of sulfate and magnesium scale by modifying polyaspartic acid derivatives with sulfonylphosphonate.

[0034] The nitrogen-containing heterocyclic corrosion inhibitor is an alkylated benzotriazole derivative, selected from methylbenzotriazole, ethylbenzotriazole, or propylbenzotriazole. Alkyl modification enhances its adsorption capacity in high-salt environments, forming a dense adsorption film on the carbon steel surface to inhibit Cl- buildup. - It penetrates the passivation film to prevent high chloride ion corrosion of the equipment.

[0035] The alkylated benzotriazole (BTA) derivative is preferably methylbenzotriazole (TTA), ethylbenzotriazole, or propylbenzotriazole, with a purity ≥98%.

[0036] like Figure 1 As shown, a method for preparing a scale inhibitor for high-chlorine, high-calcium, and high-magnesium water includes the following steps:

[0037] S1. Add sulfophosphonate-modified polyaspartic acid derivative, natural polyphenol complexing agent, zwitterionic polycarboxylate, and nitrogen-containing heterocyclic corrosion inhibitor into a container in proportion to form a mixture.

[0038] S2. Add 5-10% anhydrous ethanol to the mixture to bring it up to the total mass of the final product, and obtain the scale inhibitor product.

[0039] S3. Add deionized water until the total mass reaches 100%, then stir and mix.

[0040] S1 also includes a step for preparing sulfonylphosphonate-modified polyaspartic acid derivatives, the specific steps of which are as follows:

[0041] S11. Dissolve polyaspartic acid in deionized water to prepare a 20-30 wt% solution, add sodium 3-chloro-2-hydroxypropanesulfonate, and stir to react;

[0042] S12. Prepare a second solution of dimethyl phosphonite and 2-chloroethanol according to the molar ratio of polyaspartic acid repeating unit: dimethyl phosphonite: 2-chloroethanol = 1:0.2~0.4:0.1~0.2, and add the second solution to the first solution;

[0043] S13. After cooling, an aqueous solution of sulfonylphosphonate-modified polyaspartic acid derivative was obtained.

[0044] In S2, the mixture is continuously stirred at a stirring rate of 300~500r / min for 1~1.5h. After stirring, impurities are filtered out using a 0.22μm organic filter membrane.

[0045] An acidizing drag-reducing agent suitable for carbonate reservoirs is applied in acidized carbonate reservoirs at a concentration of 25-50 mg / L.

[0046] Scale inhibitors are added to the oil and gas field surface reinjection water / produced water treatment system, such as the inlet of the injection pump, the front end of the heat exchanger, and the front section of the filter, which are prone to scaling. Specifically, the scale inhibitor is added to the inlet of the mixer or static mixer before the reinjection pump to ensure thorough mixing with the water.

[0047] Under normal conditions, the concentration of the acidifying agent added is 25~40 mg / L; if in Cl - When the concentration is greater than 200,000 mg / L, the dosage should be adjusted to 40-50 mg / L, and the pH of the system should be synchronized to 7.0-8.0 to enhance the stability of the metal passivation film.

[0048] Therefore, the concentration of the acidifier is 25~50mg / L, which is low and reduces the cost by 30% compared with imported similar products. It can also extend the equipment maintenance cycle and has significant overall economic benefits.

[0049] Example 1

[0050] This embodiment aims to prepare a scale inhibitor with a mass of 1000g. The net mass ratio of the active components in the scale inhibitor, namely sulfophosphorus modified PASP, natural polyphenols, amphoteric polycarboxylate ester and nitrogen-containing heterocyclic corrosion inhibitor, is 72:13:12:2. The anhydrous ethanol content is 8% (corresponding to a mass of 80.0g), and the total solid content is controlled at about 30%.

[0051] (2) Raw materials and dosage

[0052] The raw materials and their specific quantities required to prepare the above products are as follows:

[0053] Sulfonylphosphonate-modified PASP intermediate solution: solid content 30%, dosage 720.0g, including net active ingredient 216.0g;

[0054] Purified EGCG: purity ≥95%, dosage 39.0g, as a natural polyphenol source;

[0055] Amphoteric polycarboxylate: solid content 40%, dosage 90.0g, including net active ingredient 36.0g;

[0056] Methylbenzotriazole: purity ≥98%, dosage 6.0g, used as a nitrogen-containing heterocyclic corrosion inhibitor;

[0057] Anhydrous ethanol: 80.0g;

[0058] Deionized water: 65.0g, replenish to 1000g.

[0059] The specific production process is as follows:

[0060] S1: Preparation of sulfonylphosphonate-modified polyaspartic acid derivative intermediate solution;

[0061] S11: Polyaspartic acid (solid content ≥90%) is added to deionized water to prepare a 20-30 wt% solution; heated to 60-70℃, and the pH is adjusted to 8.5-9.5 with NaOH solution; Temperature: 60-70℃; pH: 8.5-9.5; Polyaspartic acid solid content ≥90%; Solution concentration: 20-30 wt%

[0062] S12: Add sodium 3-chloro-2-hydroxypropanesulfonate and stir to react; wherein, the stirring rate is 300~400 r / min; the reaction time is 2~3 h.

[0063] S13: Add a mixture of dimethyl phosphonite and 2-chloroethanol in a specified ratio, and react after heating. The ratio of polyaspartic acid repeating unit: dimethyl phosphonite: 2-chloroethanol is 1:(0.2~0.4):(0.1~0.2), the reaction temperature is 75~85℃, and the reaction time is 4~5h.

[0064] S14: After cooling to room temperature, an aqueous solution of sulfonylphosphonate-modified polyaspartic acid derivative with a solid content of about 30-40% is obtained.

[0065] S2: Compound preparation and volume adjustment:

[0066] The aqueous solution of the sulfonylphosphonate synergistic modified polyaspartic acid derivative obtained from S1, the natural polyphenol complexing agent, the zwitterionic polycarboxylate, and the nitrogen-containing heterocyclic corrosion inhibitor were added to the compounding tank according to the target net mass ratio.

[0067] Add 5-10% anhydrous ethanol (by weight of the final product) to the compounding tank, then add deionized water to bring the total mass to 100%, with the total solids content controlled at 25-35%. After stirring and mixing, filter the mixture. The temperature is 30-40℃, the stirring rate is 300-500 r / min, and the stirring time is 1-1.5 h. Filter the mixture through a 0.22 μm organic filter membrane.

[0068] (3) Test conditions and test results

[0069] The descaling agent solution prepared in Example 1 was subjected to performance testing under the following simulated operating conditions:

[0070] Ion concentration: Cl - =130000 mg / L, Ca 2+ =20000 mg / L, Mg 2+ =5000 mg / L;

[0071] Ambient temperature: 80℃;

[0072] Dosage concentration: 25 mg / L.

[0073] Under the above test conditions, the performance indicators of the water treatment agent prepared in this embodiment are as follows:

[0074] Scale inhibition performance: CaCO3 scale inhibition rate 90%, CaSO4 scale inhibition rate 75%, MgCO3 scale inhibition rate 80%;

[0075] Corrosion inhibition performance: The corrosion inhibition rate for A3 steel is 60%;

[0076] Biodegradability: Tested according to OECD 301B standard, the biodegradability rate is 62% after 28 days.

[0077] Comparative Example 1

[0078] This comparative example prepared a scale inhibitor with a mass of 1000g. The net mass ratio of the active components in the scale inhibitor, namely sulfophosphorus modified PASP, natural polyphenols, amphoteric polycarboxylate ester and nitrogen-containing heterocyclic corrosion inhibitor, was 62:14:14:2. The anhydrous ethanol content was 8% (corresponding to a mass of 80.0g), and the total solid content was controlled at about 30%.

[0079] The specific production process is as follows:

[0080] S1: Preparation of sulfonylphosphonate-modified polyaspartic acid derivative intermediate solution;

[0081] S11: Polyaspartic acid (solid content ≥90%) is added to deionized water to prepare a 20-30 wt% solution; heated to 60-70℃, and the pH is adjusted to 8.5-9.5 with NaOH solution; Temperature: 60-70℃; pH: 8.5-9.5; Polyaspartic acid solid content ≥90%; Solution concentration: 20-30 wt%

[0082] S12: Add sodium 3-chloro-2-hydroxypropanesulfonate and stir to react; wherein, the stirring rate is 300~400 r / min; the reaction time is 2~3 h.

[0083] S13: Add a mixture of dimethyl phosphonite and 2-chloroethanol in a specified ratio, and react after heating. The ratio of polyaspartic acid repeating unit: dimethyl phosphonite: 2-chloroethanol is 1:(0.2~0.4):(0.1~0.2), the reaction temperature is 75~85℃, and the reaction time is 4~5h.

[0084] S14: After cooling to room temperature, an aqueous solution of sulfonylphosphonate-modified polyaspartic acid derivative with a solid content of about 30-40% is obtained.

[0085] S2: Compound preparation and volume adjustment:

[0086] The aqueous solution of the sulfonylphosphonate synergistic modified polyaspartic acid derivative obtained from S1, the natural polyphenol complexing agent, the zwitterionic polycarboxylate, and the nitrogen-containing heterocyclic corrosion inhibitor were added to the compounding tank according to the target net mass ratio.

[0087] Add 5-10% anhydrous ethanol (by weight of the final product) to the compounding tank, then add deionized water to bring the total mass to 100%, with the total solids content controlled at 25-35%. After stirring and mixing, filter the mixture. The temperature is 30-40℃, the stirring rate is 300-500 r / min, and the stirring time is 1-1.5 h. Filter the mixture through a 0.22 μm organic filter membrane.

[0088] (3) Test conditions and test results

[0089] The descaling agent solution prepared in this embodiment was subjected to performance testing under the following simulated operating conditions:

[0090] Ion concentration: Cl - =130000 mg / L, Ca 2+ =20000 mg / L, Mg 2+ =5000 mg / L;

[0091] Ambient temperature: 80℃;

[0092] Dosage concentration: 25 mg / L.

[0093] Under the above test conditions, the performance indicators of the water treatment agent prepared in this embodiment are as follows:

[0094] Scale inhibition performance: CaCO3 scale inhibition rate 82%, CaSO4 scale inhibition rate 75%, MgCO3 scale inhibition rate 80%;

[0095] Corrosion inhibition performance: The corrosion inhibition rate for A3 steel is 60%;

[0096] Biodegradability: Tested according to OECD 301B standard, the biodegradability rate is 62% after 28 days.

[0097] Comparative Example 2

[0098] This comparative example prepared a scale inhibitor with a mass of 1000g. The net mass ratio of the active components in the scale inhibitor, namely sulfophosphorus modified PASP, natural polyphenols, amphoteric polycarboxylate ester and nitrogen-containing heterocyclic corrosion inhibitor, was 72:8:16:2. The anhydrous ethanol content was 8% (corresponding to a mass of 80.0g), and the total solid content was controlled at about 30%.

[0099] The specific production process is as follows:

[0100] S1: Preparation of sulfonylphosphonate-modified polyaspartic acid derivative intermediate solution;

[0101] S11: Polyaspartic acid (solid content ≥90%) is added to deionized water to prepare a 20-30 wt% solution; heated to 60-70℃, and the pH is adjusted to 8.5-9.5 with NaOH solution; Temperature: 60-70℃; pH: 8.5-9.5; Polyaspartic acid solid content ≥90%; Solution concentration: 20-30 wt%

[0102] S12: Add sodium 3-chloro-2-hydroxypropanesulfonate and stir to react; wherein, the stirring rate is 300~400 r / min; the reaction time is 2~3 h.

[0103] S13: Add a mixture of dimethyl phosphonite and 2-chloroethanol in a specified ratio, and react after heating. The ratio of polyaspartic acid repeating unit: dimethyl phosphonite: 2-chloroethanol is 1:(0.2~0.4):(0.1~0.2), the reaction temperature is 75~85℃, and the reaction time is 4~5h.

[0104] S14: After cooling to room temperature, an aqueous solution of sulfonylphosphonate-modified polyaspartic acid derivative with a solid content of about 30-40% is obtained.

[0105] S2: Compound preparation and volume adjustment:

[0106] The aqueous solution of the sulfonylphosphonate synergistic modified polyaspartic acid derivative obtained from S1, the natural polyphenol complexing agent, the zwitterionic polycarboxylate, and the nitrogen-containing heterocyclic corrosion inhibitor were added to the compounding tank according to the target net mass ratio.

[0107] Add 5-10% anhydrous ethanol (by weight of the final product) to the compounding tank, then add deionized water to bring the total mass to 100%, with the total solids content controlled at 25-35%. After stirring and mixing, filter the mixture. The temperature is 30-40℃, the stirring rate is 300-500 r / min, and the stirring time is 1-1.5 h. Filter the mixture through a 0.22 μm organic filter membrane.

[0108] (3) Test conditions and test results

[0109] The descaling agent solution prepared in this embodiment was subjected to performance testing under the following simulated operating conditions:

[0110] Ion concentration: Cl - =130000 mg / L, Ca 2+ =20000 mg / L, Mg 2+ ⁺=5000mg / L;

[0111] Ambient temperature: 80℃;

[0112] Dosage concentration: 25 mg / L.

[0113] Under the above test conditions, the performance indicators of the water treatment agent prepared in this embodiment are as follows:

[0114] Scale inhibition performance: CaCO3 scale inhibition rate 85%, CaSO4 scale inhibition rate 70%, MgCO3 scale inhibition rate 70%;

[0115] Corrosion inhibition performance: The corrosion inhibition rate for A3 steel is 45%;

[0116] Biodegradability: Tested according to OECD 301B standard, the biodegradability rate is 60% after 28 days.

[0117] Comparative Example 3

[0118] In this comparative example, a scale inhibitor with a mass of 1000g was prepared. The net mass ratio of the active components in the scale inhibitor, namely sulfophosphorus modified PASP, natural polyphenols and nitrogen-containing heterocyclic corrosion inhibitor, was 86:14:2. The anhydrous ethanol content was 8% (corresponding to a mass of 80.0g), and the total solid content was controlled at about 30%.

[0119] The specific production process is as follows:

[0120] S1: Preparation of sulfonylphosphonate-modified polyaspartic acid derivative intermediate solution;

[0121] S11: Polyaspartic acid (solid content ≥90%) is added to deionized water to prepare a 20-30 wt% solution; heated to 60-70℃, and the pH is adjusted to 8.5-9.5 with NaOH solution; Temperature: 60-70℃; pH: 8.5-9.5; Polyaspartic acid solid content ≥90%; Solution concentration: 20-30 wt%

[0122] S12: Add sodium 3-chloro-2-hydroxypropanesulfonate and stir to react; wherein, the stirring rate is 300~400 r / min; the reaction time is 2~3 h.

[0123] S13: Add a mixture of dimethyl phosphonite and 2-chloroethanol in a specified ratio, and react after heating. The ratio of polyaspartic acid repeating unit: dimethyl phosphonite: 2-chloroethanol is 1:(0.2~0.4):(0.1~0.2), the reaction temperature is 75~85℃, and the reaction time is 4~5h.

[0124] S14: After cooling to room temperature, an aqueous solution of sulfonylphosphonate-modified polyaspartic acid derivative with a solid content of about 30-40% is obtained.

[0125] S2: Compound preparation and volume adjustment:

[0126] The aqueous solution of the sulfonylphosphonate synergistic modified polyaspartic acid derivative obtained from S1, the natural polyphenol complexing agent, and the nitrogen-containing heterocyclic corrosion inhibitor were added to the compounding tank according to the target net mass ratio.

[0127] Add 5-10% anhydrous ethanol (by weight of the final product) to the compounding tank, then add deionized water to bring the total mass to 100%, with the total solids content controlled at 25-35%. After stirring and mixing, filter the mixture. The temperature is 30-40℃, the stirring rate is 300-500 r / min, and the stirring time is 1-1.5 h. Filter the mixture through a 0.22 μm organic filter membrane.

[0128] (3) Test conditions and test results

[0129] The descaling agent solution prepared in this embodiment was subjected to performance testing under the following simulated operating conditions:

[0130] Ion concentration: Cl - =130000 mg / L, Ca 2+ =20000 mg / L, Mg 2+ =5000 mg / L;

[0131] Ambient temperature: 80℃;

[0132] Dosage concentration: 25 mg / L.

[0133] Under the above test conditions, the performance indicators of the water treatment agent prepared in this embodiment are as follows:

[0134] Scale inhibition performance: CaCO3 scale inhibition rate 88%, CaSO4 scale inhibition rate 55%, MgCO3 scale inhibition rate 65%;

[0135] Corrosion inhibition performance: The corrosion inhibition rate for A3 steel is 58%;

[0136] Biodegradability: Tested according to OECD 301B standard, the biodegradability rate is 61% after 28 days.

[0137] By comparing Comparative Examples 1 to 4, as shown in Table 1:

[0138] Table 1 Comparison of Results

[0139]

[0140] Therefore, the scale inhibitor prepared in Example 1 of this application can achieve the best scale inhibition effect.

[0141] Specific implementation method:

[0142] Taking a scale inhibitor with an annual production of 5,000 tons as an example, using the optimal formulation of Example 1 (sulfonylphosphonate modified PASP: natural polyphenols: amphoteric polycarboxylate esters: nitrogen-containing heterocyclic corrosion inhibitor = 72:13:12:2, ethanol content 8%, total solid content ≈29.7%), the raw material consumption is shown in Table 2:

[0143] Table 2 Raw Material Consumption Specifications

[0144]

[0145] (2) Selection of core equipment

[0146] Referring to the industrial equipment configuration standards for compound water treatment agents, and considering the reaction characteristics of this product, the equipment selection is shown in Table 3:

[0147] Table 3 Equipment Selection

[0148]

[0149] (3) Detailed production process

[0150] 1. Intermediate synthesis process

[0151] Start the 10m³ modified reactor, add 6.0 tons of deionized water through the automatic metering pump, turn on the jacket heating to 40°C, add 0.864 tons of polyaspartic acid solid (through the solid feeding station in a closed manner), and turn on the anchor stirrer (speed 150r / min) until completely dissolved to form a 20wt% polyaspartic acid solution.

[0152] The pH was adjusted to 8.5-9.5 using a NaOH metering pump, the temperature was raised to 65°C, and 0.432 tons of sodium 3-chloro-2-hydroxypropanesulfonate solution was added, maintaining stirring for 2.5 hours. Subsequently, a mixture of 0.288 tons of dimethyl phosphonite and 0.144 tons of 2-chloroethanol was added dropwise at a uniform rate using a metering pump (dropping time 1 hour), the temperature was raised to 80°C, and the reaction was maintained at this temperature for 4.5 hours. After the reaction was completed, the temperature was lowered to 30°C using a jacketed cooling water system to obtain a sulfonylphosphonate-modified PASP intermediate solution (solid content approximately 30%), which was transferred to an intermediate storage tank for later use.

[0153] 2. Compounding process

[0154] Start the 20m³ compounding tank, add 12.982 tons of deionized water and 1.334 tons of anhydrous ethanol, and start the paddle stirrer (200 rpm) to mix thoroughly. Add the above intermediate solution (containing 1.152 tons of net active ingredient) through a metering pump, and stir for 10 minutes. Then, add 0.208 tons of purified EGCG derivative and 0.032 tons of methylbenzotriazole through the solids feeding station, and continue stirring for 30 minutes until the solids are completely dissolved. Finally, add 0.500 tons of zwitterionic polycarboxylate aqueous solution (containing 0.200 tons of net active ingredient), raise the temperature to 35°C, and maintain the temperature with stirring for 1 hour. During this time, monitor the solid content with an online refractometer to ensure it reaches 29.5%~30.0%.

[0155] 3. Filtration and filling process

[0156] The compounded solution is filtered through a precision filter to remove impurities with a particle size >0.22μm, yielding a transparent light brown filtrate. Samples are taken for testing of CaCO3 scale inhibition rate (≥90%), corrosion inhibition rate (≥60%), and appearance (uniform transparency). Once qualified, the filtrate is transferred to the finished product storage tank. It is then packaged into 25kg plastic drums or 1000L IBC containers via the filling production line, labeled with the product batch, production date, and quality indicators, and stored in the warehouse (at room temperature, avoiding direct sunlight).

[0157] (4) Key points of process control

[0158] Intermediate quality control: Each batch of intermediates must be tested for molecular weight (gel permeation chromatography) and functional group content (potentiometric titration) to ensure that the number average molecular weight is 3000~6000 Da, the sulfonic acid group grafting rate is 25~35%, and the phosphonate group grafting rate is 8~12%. Non-conforming products must be reworked after adjusting the reaction parameters.

[0159] Temperature control during compounding: Natural polyphenols are easily oxidized and degraded at temperatures above 45℃. The compounding process must be strictly controlled at temperatures below 40℃, and nitrogen protection (0.5 m³ / h) is used to further prevent oxidation.

[0160] Filtration performance monitoring: Replace the precision filter membrane every 4 hours and periodically test the turbidity of the filtered solution (≤5 NTU) to avoid product turbidity caused by filter membrane clogging.

[0161] Environmental and safety measures: The small amount of cleaning wastewater (containing ethanol and trace raw materials) generated during the production process is collected in a wastewater treatment pond and discharged after being degraded by biochemical methods to meet standards; the ethanol storage tank area is equipped with explosion-proof ventilation equipment and fire-fighting equipment, and operators wear acid and alkali resistant gloves and goggles, which comply with chemical safety regulations.

[0162] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A scale inhibitor suitable for water with high chlorine, high calcium, and high magnesium content, characterized in that, The solution comprises a deionized water-anhydrous ethanol solution and four active components. These four active components, based on their total mass of 100%, are as follows by mass percentage: 70-74% sulfonylphosphonate-modified polyaspartic acid derivative, 10-13% natural polyphenol complexing agent, 12-14% zwitterionic polycarboxylate, and 1-2% nitrogen-containing heterocyclic corrosion inhibitor. Based on the total mass of the descaling agent, the total mass fraction of the four active components is 25-35%, the mass fraction of anhydrous ethanol is 5-10%, and the remainder is deionized water. The sulfonylphosphonate-modified polyaspartic acid derivative is a functionalized polymer with polyaspartic acid as the main chain, grafted with sulfonic acid groups and phosphonate groups.

2. The scale inhibitor suitable for high-chlorine, high-calcium, and high-magnesium water quality according to claim 1, characterized in that, The repeating unit structure of the polyaspartic acid backbone has the general formula -[NH-CH(CO2H)-CH2-CO]-, and the number average molecular weight is 3000Da~6000Da; In every 100 repeating units on the main chain, 25-35 nitrogen atoms are bonded with -CH2CH(OH)CH2SO3. - The group is substituted and 8 to 12 -P(O)(OR)OH groups are grafted, wherein R is a C1-C4 alkyl group.

3. A scale inhibitor suitable for high-chlorine, high-calcium, and high-magnesium water quality according to claim 2, characterized in that, The natural polyphenol complexing agent is a plant polyphenol containing a catechol structure, preferably a purified epigallocatechin gallate derivative.

4. A scale inhibitor suitable for high-chlorine, high-calcium, and high-magnesium water as described in claim 3, characterized in that, The zwitterionic polycarboxylate includes betaine-type side chains with a side chain density of 1.0~1.2 mmol / g.

5. A scale inhibitor suitable for high-chlorine, high-calcium, and high-magnesium water as described in claim 3, characterized in that, The nitrogen-containing heterocyclic corrosion inhibitor is an alkylated benzotriazole derivative, selected from methylbenzotriazole, ethylbenzotriazole or propylbenzotriazole.

6. A method for preparing a scale inhibitor for high-chlorine, high-calcium, and high-magnesium water, characterized in that, Includes the following steps: S1. Add sulfophosphonate-modified polyaspartic acid derivative, natural polyphenol complexing agent, zwitterionic polycarboxylate, and nitrogen-containing heterocyclic corrosion inhibitor into a container in proportion to form a mixture. S2. Add 5-10% anhydrous ethanol to the mixture to bring it up to the total mass of the final product, and obtain the scale inhibitor product. S3. Add deionized water until the total mass reaches 100%, then stir and mix.

7. A method for preparing a scale inhibitor for high-chlorine, high-calcium, and high-magnesium water according to claim 6, characterized in that, S1 also includes a step for preparing sulfonylphosphonate-modified polyaspartic acid derivatives, the specific steps of which are as follows: S11. Dissolve polyaspartic acid in deionized water to prepare a 20-30 wt% solution, add sodium 3-chloro-2-hydroxypropanesulfonate, and stir to react; S12. Prepare a second solution of dimethyl phosphonite and 2-chloroethanol according to the molar ratio of polyaspartic acid repeating unit: dimethyl phosphonite: 2-chloroethanol = 1:0.2~0.4:0.1~0.2, and add the second solution to the first solution; S13. After cooling, an aqueous solution of sulfonylphosphonate-modified polyaspartic acid derivative was obtained.

8. A method for preparing a scale inhibitor for high-chlorine, high-calcium, and high-magnesium water according to claim 7, characterized in that, In step S2, the mixture is continuously stirred at a stirring rate of 300-500 r / min for 1-1.5 h. After stirring is completed, impurities are filtered out using a 0.22 μm organic filter membrane.

9. The application of the scale inhibitor as described in any one of claims 1 to 5 in high-chlorine, high-calcium, and high-magnesium water.

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